1. Field of the Invention
Apparatuses consistent with the present invention relate to a centrifugal force based microfluidic device, a microfluidic system including the microfluidic device and a method of determining a home position of the microfluidic device using the microfluidic system.
2. Description of the Related Art
Generally, a microfluidic device has a structure which includes a chamber storing a minute amount of a fluid, a channel through which the fluid flows, a valve for controlling flow of the fluid, and various functional units receiving the fluid to perform predetermined functions thereon. A biochip is obtained by arranging such a microfluidic device on a chip-type substrate and is used to analyze the performance of various assays including biologic reactions. In particular, a device that is designed to perform multiple step processes and manipulations using a single chip is referred to as a lab-on-a-chip.
A driving pressure is generally required to transfer a fluid within a microfluidic device. Capillary pressure or pressure generated by a specifically prepared pump is used to create the driving pressure. A lab compact disk (CD) or a lab-on a disk is a recently-suggested microfluidic device obtained by arranging microfluidic structures on a compact disk-shaped platform and uses centrifugal forces. This is referred to as a lab CD or a lab-on-a-disk.
Such centrifugal force based microfluidic devices perform sample reactions according to their own uses (e.g. immune serum tests and gene test) in chambers. Reaction results are detected through corresponding reaction detectors. In order to perform the sample reactions in the microfluidic devices and detect the reaction results using the reaction detectors, it is necessary that positions of valves, functional units, and chambers for detecting the reaction disposed on a disk-type platform should be correctly determined.
FIG. 1 is a plan view of a related art microfluidic device, which is disclosed in U.S. Pat. No. 6,992,278.
Referring to FIG. 1, a mark 15 is made on a circumference of a platform 11 of the related art microfluidic device 10 to mark a home position. By emitting light onto the mark 15 to detect reflected light and setting the mark 15 as the home position, relative positions of valves, functional units and chambers can be determined. However, in the related art, the mark 15 should be formed to have a relatively large size in order to reduce detection errors for the home position. In addition, since light may be diffused, determination error for the home position may be increased during emitting and reflecting light.